1
|
Wang H, Shao L, Liu Y, Sun Y, Zou B, Zhao Y, Wang Y, Li X, Dai R. Changes in stresses sensitivity of ohmic heating-induced sublethally injured Staphylococcus aureus during repair: Potential mechanisms at the cellular and molecular levels. Int J Food Microbiol 2024; 422:110814. [PMID: 38972103 DOI: 10.1016/j.ijfoodmicro.2024.110814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/19/2024] [Accepted: 06/27/2024] [Indexed: 07/09/2024]
Abstract
Ohmic heating (OH), an emerging food processing technology employed in the food processing industry, raises potential food safety concerns due to the recovery of sublethally injured pathogens such as Staphylococcus aureus (S. aureus). In the present study, sensitivity to various stress conditions and the changes in cellular-related factors of OH-injured S. aureus during repair were investigated. The results indicated that liquid media differences (nutrient broth (NB), phosphate-buffered saline (PBS), milk, and cucumber juice) affected the recovery process of injured cells. Nutrient enrichment determines the bacterial repair rate, and the rates of repair for these media were milk > NB > cucumber juice > PBS. The sensitivity of injured cells to various stressors, including different acids, temperature, nisin, simulated gastric fluid, and bile salt, increased during the injury phase and subsequently diminished upon repair. Additionally, the intracellular ATP content, enzyme activities (Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and T-ATPase) and ion concentrations (Mg2+, K+, and Ca2+) gradually increased during repair. After 5 h of repair, the intracellular substances content of cell's was significantly higher than that of the injured bacteria without repair, while some indicators (e.g., Na+/K+-ATPase, K+, and Ca2+) were not restored to the untreated level. The results of this study indicated that OH-injured S. aureus exhibited strengthened resistance post-recovery, potentially due to the restoration of cellular structures. These findings have implications for optimizing food storage conditions and advancing OH processes in the food industry.
Collapse
Affiliation(s)
- Han Wang
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Lele Shao
- College of Tea & Food Science and Technology, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, PR China
| | - Yana Liu
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yingying Sun
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Bo Zou
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yijie Zhao
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yuhan Wang
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Xingmin Li
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Ruitong Dai
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China.
| |
Collapse
|
2
|
Lee JI, Kim SS, Kang DH. Characteristics of Staphylococcus aureus biofilm matured in tryptic soy broth, low-fat milk, or whole milk samples along with inactivation by 405 nm light combined with folic acid. Food Microbiol 2023; 116:104350. [PMID: 37689424 DOI: 10.1016/j.fm.2023.104350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 09/11/2023]
Abstract
In the present study, the characteristics of Staphylococcus aureus biofilms matured in tryptic soy broth (TSB), low-fat milk, or whole milk samples were identified along with their resistance to 405 nm light with or without folic acid. Phenotypic properties of carbohydrate and protein contents in extracellular polymeric substance (EPS) of S. aureus biofilms matured in different conditions were identified. The carbohydrate content was higher in the biofilm matured in low-fat milk (1.27) than the samples matured in whole milk (0.58) and TSB (0.10). Protein content in the EPS of biofilm was higher in the sample matured in whole milk (6.59) than the samples matured in low-fat milk (3.24) and TSB (2.08). Moreover, the maturation condition had a significant effect on the membrane lipid composition of the biofilm, producing more unsaturated fatty acids in biofilm matured in milk samples. These changes in biofilm matured in milk samples increased the resistance of S. aureus to 405 nm light in the presence of folic acid (LFA). Additionally, transcriptomic analysis was conducted to identify the response of S. aureus biofilm to LFA treatment. Several genes related to DNA and protein protection from oxidative stress along with biofilm accumulation were overexpressed in the LFA-treated biofilms. These results indicate the maturation of S. aureus biofilm in various samples and the biofilms responses to bactericidal treatments.
Collapse
Affiliation(s)
- Jae-Ik Lee
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea
| | - Sang-Soon Kim
- Department of Food Engineering, Dankook University, Cheonan, Chungnam, 31116, Republic of Korea
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea.
| |
Collapse
|
3
|
Kim SY, Kim SH, Park SH. Inactivation of Foodborne Pathogen Biofilm Cells Using a Combination Treatment with Gaseous Chlorine Dioxide and Aerosolized Sanitizers. J Food Prot 2023; 86:100105. [PMID: 37196846 DOI: 10.1016/j.jfp.2023.100105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 05/07/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023]
Abstract
A biofilm is a three-dimensional microbial community, which is difficult to completely control with a typical sanitizer owing to its complex structure. The aim of this study was to establish a system for the combined treatment of biofilms with 10 ppmv gaseous chlorine dioxide (ClO2) and antimicrobial agents (2% citric acid, 2% hydrogen peroxide [H2O2], and 100 ppm peracetic acid [PAA]), and to investigate the synergistic microbicidal efficacy of the combination treatments to inactivate Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 in biofilms. The antimicrobial agents were aerosolized using a humidifier on top of a chamber to achieve a relative humidity of 90% (within a range of ±2%). While biofilm treatment with the aerosolized antimicrobial agents for 20 min inactivated approximately 1 log CFU/cm2 (0.72-1.26 log CFU/cm2) of the pathogens and the gaseous ClO2 gas treatment for 20 min inactivated <3 log CFU/cm2 (2.19-2.77 log CFU/cm2), combination treatment with citric acid, H2O2, and PAA for 20 min achieved microbial reductions of 2.71-3.79, 4.56-5.12, and 4.45-4.67 log CFU/cm2, respectively. Our study demonstrates that foodborne pathogens in biofilms can be inactivated by combining gaseous ClO2 treatment with aerosolized antimicrobial agents. The results of this study provide baseline data for the food industry to help control foodborne pathogens in biofilms on inaccessible surfaces.
Collapse
Affiliation(s)
- Se-Yeon Kim
- Department of Food Science and Technology, Kongju National University, Yesan, Chungnam 32439, Republic of Korea
| | - Soo-Hwan Kim
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Sang-Hyun Park
- Department of Food Science and Technology, Kongju National University, Yesan, Chungnam 32439, Republic of Korea.
| |
Collapse
|
4
|
Biofilm Formation and Control of Foodborne Pathogenic Bacteria. Molecules 2023; 28:molecules28062432. [PMID: 36985403 PMCID: PMC10058477 DOI: 10.3390/molecules28062432] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/17/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023] Open
Abstract
Biofilms are microbial aggregation membranes that are formed when microorganisms attach to the surfaces of living or nonliving things. Importantly, biofilm properties provide microorganisms with protection against environmental pressures and enhance their resistance to antimicrobial agents, contributing to microbial persistence and toxicity. Thus, bacterial biofilm formation is part of the bacterial survival mechanism. However, if foodborne pathogens form biofilms, the risk of foodborne disease infections can be greatly exacerbated, which can cause major public health risks and lead to adverse economic consequences. Therefore, research on biofilms and their removal strategies are very important in the food industry. Food waste due to spoilage within the food industry remains a global challenge to environmental sustainability and the security of food supplies. This review describes bacterial biofilm formation, elaborates on the problem associated with biofilms in the food industry, enumerates several kinds of common foodborne pathogens in biofilms, summarizes the current strategies used to eliminate or control harmful bacterial biofilm formation, introduces the current and emerging control strategies, and emphasizes future development prospects with respect to bacterial biofilms.
Collapse
|
5
|
Lin Z, Chen T, Zhou L, Yang H. Effect of chlorine sanitizer on metabolic responses of Escherichia coli biofilms "big six" during cross-contamination from abiotic surface to sponge cake. Food Res Int 2022; 157:111361. [PMID: 35761623 DOI: 10.1016/j.foodres.2022.111361] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/19/2022] [Accepted: 05/10/2022] [Indexed: 11/04/2022]
Abstract
The effect of chlorine on Escherichia coli biofilm O157:H7 are well established; however, the effect on biofilm adhesion to food as well as the six emerging E. coli serotypes ("big six") have not been fully understood. Chlorine sanitization with 1-min 100 mg/L was applied against seven pathogenic E. coli (O111, O121:H19, O45:H2, O26:H11, O103:H11, O145, and O157:H7) biofilms on high-density polyethylene (HDPE) and stainless steel (SS) coupons, respectively. Using sponge cake as a food model, the adhesion behavior was evaluated by comparison of bacteria transfer rate before and after treatment. Besides, the metabolic profiles of biofilms were analyzed by nuclear magnetic resonance (NMR) spectrometer. A significant decrease in transfer rate (79% decline on SS and 33% decline on HDPE) was recorded as well as the distinctive pattern between SS and HDPE coupons was also noticed, with a low population (6-7 log CFU/coupon) attached and low survivals (0-3 log CFU/coupon) upon chlorine on SS, while high population (7-8 log CFU/coupon) attached and high survivals (5-7 log CFU/coupon) on HDPE. Moreover, O121:H19 and O26:H11 demonstrated the highest resistance to chlorine with the least metabolic status and pathways affected. O103:H11, O145, and O111 followed similar metabolic patterns on both surfaces. Distinct metabolic patterns were found in O45:H2 and O157:H7, where the former had more affected metabolic status and pathways on SS but less on HDPE, whereas the latter showed an opposite trend. Overall, a potential contamination source of STEC infection in flour products was demonstrated and metabolic changes induced by chlorine were revealed by NMR-based metabolomics, which provides insights to avoid "big six" biofilms contamination in food.
Collapse
Affiliation(s)
- Zejia Lin
- Department of Food Science & Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China
| | - Tong Chen
- Department of Food Science & Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China
| | - Lehao Zhou
- Department of Food Science & Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China
| | - Hongshun Yang
- Department of Food Science & Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.
| |
Collapse
|
6
|
Park HW, Balasubramaniam VM, Snyder AB, Sekhar JA. Influence of Superheated Steam Temperature and Moisture Exchange on the Inactivation of Geobacillus stearothermophilus Spores in Wheat Flour-Coated Surfaces. FOOD BIOPROCESS TECH 2022. [DOI: 10.1007/s11947-022-02830-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
7
|
The combined effect of folic acid and 365–405 nm light emitting diode for inactivation of foodborne pathogens and its bactericidal mechanisms. Int J Food Microbiol 2022; 373:109704. [DOI: 10.1016/j.ijfoodmicro.2022.109704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/14/2022] [Accepted: 05/02/2022] [Indexed: 11/24/2022]
|
8
|
Cha MY, Ha JW. Low-energy X-ray irradiation effectively inactivates major foodborne pathogen biofilms on various food contact surfaces. Food Microbiol 2022; 106:104054. [DOI: 10.1016/j.fm.2022.104054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 11/04/2022]
|
9
|
Growth temperature-induced changes in resistance of Listeria monocytogenes and Yersinia enterocolitica to X-ray irradiation. Food Microbiol 2022; 105:104029. [DOI: 10.1016/j.fm.2022.104029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 03/16/2022] [Accepted: 03/16/2022] [Indexed: 11/30/2022]
|
10
|
Dhivya R, Rajakrishnapriya VC, Sruthi K, Chidanand DV, Sunil CK, Rawson A. Biofilm combating in the food industry: Overview, non‐thermal approaches, and mechanisms. J FOOD PROCESS PRES 2022. [DOI: 10.1111/jfpp.16282] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- R. Dhivya
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - V. C. Rajakrishnapriya
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - K. Sruthi
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - D. V. Chidanand
- Industry Academia Cell National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - C. K. Sunil
- Department of Food Engineering National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| | - Ashish Rawson
- Department of Food Safety and Quality Testing National Institute of Food Technology, Entrepreneurship and Management (NIFTEM) ‐ Thanjavur Thanjavur India
| |
Collapse
|
11
|
Kim SH, Jyung S, Kang DH. Comparative study of Salmonella Typhimurium biofilms and their resistance depending on cellulose secretion and maturation temperatures. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2021.112700] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
12
|
Sun J, Wang D, Sun Z, Liu F, Du L, Wang D. The combination of ultrasound and chlorogenic acid to inactivate Staphylococcus aureus under planktonic, biofilm, and food systems. ULTRASONICS SONOCHEMISTRY 2021; 80:105801. [PMID: 34688141 PMCID: PMC8551818 DOI: 10.1016/j.ultsonch.2021.105801] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 10/14/2021] [Accepted: 10/16/2021] [Indexed: 05/03/2023]
Abstract
This study aimed to investigate the mechanism of different treatments, namely, ultrasound (US), chlorogenic acid (CA), and ultrasound combined with chlorogenic acid (US plus CA) on the inactivation of Staphylococcus aureus planktonic and biofilm cells. Results showed that the combined treatment of US and CA exhibited remarkable synergistic antibacterial and antibiofilm effects. Scanning electron microscopy images indicated that the combined treatment of US and CA caused the most serious damage to the cell morphology. Confocal laser scanning microscopy images revealed that the combined treatment led to sharp increase and severe damage to the permeability of the cell membrane, causing the release of ATP and nucleic acids and decreasing the exopolysaccharide contents in S. aureus biofilm. Finally, the combined treatment of US plus 1% CA for 60 min inactivated S. aureus cells by 1.13 lg CFU/g on mutton. Thus, the combined treatment of US and CA had synergistic effect against S. aureus under planktonic, biofilm, and food systems.
Collapse
Affiliation(s)
- Jinyue Sun
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China; Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Debao Wang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China; Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Zhilan Sun
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China; Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Fang Liu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China; Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - Lihui Du
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
| | - Daoying Wang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China; Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| |
Collapse
|
13
|
Recovery and virulence factors of sublethally injured Staphylococcus aureus after ohmic heating. Food Microbiol 2021; 102:103899. [PMID: 34809931 DOI: 10.1016/j.fm.2021.103899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 08/20/2021] [Accepted: 09/09/2021] [Indexed: 11/22/2022]
Abstract
Ohmic heating (OH) is an alternative thermal processing technique, which is widely used to pasteurize or sterilize food. However, sublethally injured Staphylococcus aureus induced by OH is a great concern to food safety. The recovery of injured S. aureus by OH and virulence factor changes during recovery were investigated in this study. The liquid media (phosphate-buffered saline, buffered peptone water and nutrient broth (NB)), temperature (4, 25 and 37 °C) and pH (6.0, 7.2 and 8.0) influenced the recovery rate and the injured cells completely repaired in NB at 37 °C, pH 7.2 with the shortest time of 2 h. The biofilm formation ability, mannitol fermentation, hemolysis, and coagulase activities decreased in injured S. aureus and recovered during repair process. Quantitative real-time PCR showed the expression of sek, clfB and lukH involved in virulence factors increased during recovery. The results indicated that the virulence factors of injured S. aureus recovered after repair.
Collapse
|
14
|
Lattice Boltzmann Method in Modeling Biofilm Formation, Growth and Detachment. SUSTAINABILITY 2021. [DOI: 10.3390/su13147968] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biofilms are a complex and heterogeneous aggregation of multiple populations of microorganisms linked together by their excretion of extracellular polymer substances (EPS). Biofilms can cause many serious problems, such as chronic infections, food contamination and equipment corrosion, although they can be useful for constructive purposes, such as in wastewater treatment, heavy metal removal from hazardous waste sites, biofuel production, power generation through microbial fuel cells and microbially enhanced oil recovery; however, biofilm formation and growth are complex due to interactions among physicochemical and biological processes under operational and environmental conditions. Advanced numerical modeling techniques using the lattice Boltzmann method (LBM) are enabling the prediction of biofilm formation and growth and microbial community structures. This study is the first attempt to perform a general review on major contributions to LBM-based biofilm models, ranging from pioneering efforts to more recent progress. We present our understanding of the modeling of biofilm formation, growth and detachment using LBM-based models and present the fundamental aspects of various LBM-based biofilm models. We describe how the LBM couples with cellular automata (CA) and individual-based model (IbM) approaches and discuss their applications in assessing the spatiotemporal distribution of biofilms and their associated parameters and evaluating bioconversion efficiency. Finally, we discuss the main features and drawbacks of LBM-based biofilm models from ecological and biotechnological perspectives and identify current knowledge gaps and future research priorities.
Collapse
|
15
|
Park HW, Xu J, Balasubramaniam V, Snyder AB. The effect of water activity and temperature on the inactivation of Enterococcus faecium in peanut butter during superheated steam sanitation treatment. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.107942] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
16
|
Lin L, Chen M, Ou J, Yan W. Kinetics of Staphylococcus aureus growth and Enterotoxin A production in milk under shaking and static conditions. Food Res Int 2021; 143:110298. [PMID: 33992318 DOI: 10.1016/j.foodres.2021.110298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
Numerous studies on bacterial growth or survival predictive models have been conducted since the establishment of predictive microbiology. However, limited research focused on the prediction of bacteria-producing enterotoxins, which are often the causative agents of food-borne diseases. This study aimed to determine an appropriate kinetic model of staphylococcal enterotoxin A (SEA) production in milk after contamination with Staphylococcus aureus. An S. aureus strain producing SEA was inoculated into milk with an initial inoculum concentration of approximately 3.0 log CFU/mL. All samples were incubated for 30-48 h at 20 °C ± 1 °C, 28 °C ± 1 °C, and 36 °C ± 1 °C separately under shaking or static conditions. Duplicate samples were carried out at appropriate intervals to count the number of S. aureus colonies and detect the concentration of SEA. Experimental results showed that the SEA concentration curves under all experimental conditions were sigmoidal and consisted of three phases: lag, exponential, and stationary. Thus, the modified Gompertz model was used to describe the profile of SEA concentration in milk during the incubation. A good fitting accuracy (R2 > 0.97) indicated that the modified Gompertz model was appropriate. In addition to temperature, shaking during incubation also affected the maximal production rate of SEA and the maximal SEA concentrations, and shortened the lag phase at lower incubation temperatures, suggesting that the mechanical movements (e.g., stirring, pumping, and flowing) during the milk processing would increase the risk of SEA occurrence. Besides, the time to detection (TTD) of SEA was found to range from 3 to 24.5 h at temperatures of 36 °C ± 1 °C-20 °C ± 1 °C, at which time the concentrations of S. aureus ranging from 5.0 log CFU/mL-6.9 log CFU/mL at the TTD. This study contributed to understanding the kinetics of SEA production and the possible factors affecting the synthesis of SEA during the manufacturing of liquid foods, such as milk.
Collapse
Affiliation(s)
- Lu Lin
- Shanghai Food Research Institute, Shanghai 200235, China
| | - Min Chen
- Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China
| | - Jie Ou
- Shanghai Ocean University, Shanghai 201306, China
| | - Weiling Yan
- Shanghai Food Research Institute, Shanghai 200235, China.
| |
Collapse
|